THE abduction of Madeleine McCann could have been a pre-planned operation, the head of the Scotland Yard inquiry said yesterday.

Elements of the mystery suggest there may have been surveillance or reconnaissance of families with young children at the holiday resort on the Algarve.

Police are now anxious to trace several blond-haired men seen close to the McCanns’ holiday apartment at Praia da Luz on or before the day Madeleine went missing.

Detective Chief Inspector Andy Redwood issued descriptions of the men whose e-fit images featured on the BBC Crimewatch appeal last night.

Mr Redwood said: “One reading of the evidence suggest the hallmarks of a pre-planned abduction and elements of surveillance. We see a number of men lurking in and around in the day.”

But the officer stressed this was only one possibility and officers were keeping an “open mind.” Police are particularly anxious to trace:

A man seen by one witness at approximately 8am on April 30, 2007, and around noon on May 2 – the day before Madeleine went missing. Both sightings were near the McCanns’ ground floor apartment 5A.

Suspect: e-fit image of man twice seen near the McCanns’ flat

One reading of the evidence suggest the hallmarks of a pre-planned abduction

Detective Chief Inspector Andy Redwood

The man was described as white, 30-35, thin, with short, light-coloured hair and spots on his face possibly caused by shaving. He had thick-framed black sunglasses and was wearing a black leather jacket with silver zips.

A white man seen near the 5A apartment around 4pm on the day Madeleine was snatched. He has blondish hair, described as quite close-shaven, aged between 30-35 years old.

A Portuguese-looking man who approached a property on the Rua do Ramalhete close to the Ocean Club complex where the McCanns were staying.

He had medium-length, wavy hair, and was about 25 to 30. He is said to have spoken good English and was seen with another man.

Suspect: one of the blond men – may be the same person as e-fit above

A charity collector who called at 5A on April 25 or 26 before the McCanns arrived. He was described as Portuguese-looking, aged 40 to 45, with short, dark hair, slightly greying at the sides.

The man was carrying a clipboard or pad, receipt book and an ID card with his photo on it. But in the photo he had a goatee beard.

Police say there were other charity collectors in the area claiming they were raising money for orphans. In reality, they may have been thieves looking for holiday apartments to burgle.

Detectives also want to trace other blond-haired men seen in the area.

Suspect: charity collector who called at the family’s holiday apartment

They include two men seen on the balcony of a nearby empty apartment and a man seen in the stairwell of the McCanns’ block.

Police have also been told about two men speaking with raised voices close to the 5A apartment about an hour after Madeleine disappeared.

When they spotted the witness, they walked away talking in hushed tones.

Suspect: man who went to a property close to the Ocean Club holiday complex